Flash Flood Warning 197, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
259 PM MST Tue Aug 17 2021

.SYNOPSIS...Widespread showers and storms will slowly diminish in
coverage and intensity later this evening and overnight. Another
round of numerous showers and storms are forecast to develop over
northern Arizona Wednesday afternoon.

Drier conditions are then expected Thursday through the weekend.
Cooler temperatures are also expected through the rest of the
week.

&&

.DISCUSSION...Numerous thunderstorms will continue to develop
along the Mogollon Rim this afternoon. Slow storm motions have
produced flash flooding, primarily in vulnerable burn scar areas,
namely the Museum Fire scar. The flash flood threat is expected to
continue through the evening hours, primarily across Coconino
County. As a result, decided to issue a Flash Flood Watch
for the aforementioned area where the best moisture and
instability is located. Storm coverage and intensity should
diminish overnight.

By Wednesday, an upper level trough will be digging into Idaho.
This will result in much stronger southwesterly flow over northern
Arizona. With monsoonal moisture remaining in place, still think
numerous showers and thunderstorms will develop along the Mogollon
Rim, then push to the north and east. Some storms could become
better organized near the AZ/UT border Wednesday afternoon,
proximate to the deeper wind shear. Large hail, damaging winds,
and flash flooding will be the primary threats.

By Thursday, some drying is forecast to overspread Arizona, with
lingering moisture keeping thunderstorm chances near the AZ/UT
border.

Dry conditions are then forecast Friday through the weekend as a
broad upper level trough is forecast to remain off the California
coast. Temperatures will be below normal through the period.

&&

.AVIATION...For the 00Z package...Scattered to numerous
thunderstorms will continue through the early evening hours. A
few storms may be severe producing brief IFR conditions, strong
outflow winds, and hail. Storms should diminish overnight, then
re-develop after 18Z Wednesday. Outside of storm activity, mainly
VFR conditions and southwest winds around 10-15 kts or less.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Scattered to numerous showers and thunderstorms
are expected to develop again Wednesday afternoon. Large hail,
localized flash flooding, and very gusty outflow winds will be the
main hazards. Winds will also become breezy out of the southwest
Wednesday. Much drier conditions are forecast Thursday.

Friday through Sunday...Drier weather is expected through the
weekend, with below normal temperatures and breezy southwest
winds.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Flash Flood Watch until 11 PM MST this evening FOR AZZ004>007-
009-012-015-016.

&&

PUBLIC...TM
AVIATION...TM
FIRE WEATHER...TM

For Northern Arizona weather information visit
weather.gov/flagstaff

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
247 PM MST TUE AUG 17 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0230 PM     FLASH FLOOD      2 E DOWNTOWN FLAGSTAFF  35.19N 111.61W
08/17/2021                   COCONINO           AZ   NWS EMPLOYEE

            ROAD CLOSURE DUE TO FLOODING.

&&

MD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
323 PM MST TUE AUG 17 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0310 PM     FLASH FLOOD      3 NNW DOWNTOWN FLAGSTAF 35.24N 111.68W
08/17/2021                   COCONINO           AZ   NWS EMPLOYEE

            ROAD IMPASSABLE DUE TO FLOODING.

&&

MD